1. The Field of the Invention
The field of the invention relates to an improved ultrasonic detector mounted on an automotive vehicle to detect an object obstructing the path of the vehicle particularly when the vehicle is traveling in reverse.
2. Description of the Prior Art
Ultrasonic devices for detection of obstructions in a vehicle's pathway are known. U.S. Pat. No. 4,103,278 (July 25, 1978 to Satake, et. al.) teaches the use of two receivers coupled to one motor driven transmitter/receiver in conjunction with a motor driven display which makes possible a visual representation on a CRT grid of the location of the obstacle. U.S. Pat. No. 4,500,977 (Feb. 19, 1985 to Gelhard) teaches wave focusing by certain shaped reflector means including concave reflectors to focus an ultrasonic beam narrowly for detection of the distance of obstacles with extreme accuracy. Included is a complex visual display with digital information provided thereon. U.S. Pat. No. 4,528,563 (July 9, 1985 to Takeuchi) utilizes 4 transmitters, 4 receivers and 4 speakers disposed at the corners of a vehicle to produce an intermittent tone in a loud speaker situated interiorly at the corner of the vehicle nearest to the obstruction. The tone provides information about the distance off of the object by means of a tone pulse period which is proportional to the distance. U.S. Pat. No. 4,561,064 (Dec. 24, 1985 to Bruggen, et.al.) utilizes separate transmitter and receiver means in combination with an undifferentiated audible tone emitted at a fixed distance and has reflecting feed back means to verify operation. U.S. Pat. No. 4,580,250 (Apr. 1, 1986 to Kago et al) teaches obstacle detection in conjunction with an intervehicle communication system utilizing front and rear mounted transducer modules. U.S. Pat. No. 4,551,722 (Nov. 5, 1985 to Tsuda et al) teaches the attenuation or elimination of false signals received from distant objects.
The prior art references do not teach a simplified device which provides timely, easily discernible and useful information to the operator while backing up. None teaches the design of a reflector which reflects outward from a single combined transmitter/receiver/transducer a broadly flattened beam widened to be contiguous to the stern of the vehicle and which is interpretable as an audio-visual signal responsive to distance off to impart instantly useful information to the operator such that his attention is not diverted unduly from the task of backing.